21+ HP from catback?
04-08-2012, 03:32 PM
#11
4th Gear Member
Thread Starter
Join Date: Apr 2008
Posts: 1,792
people have dyno'd at 365-375whp stock. looks like a regular stock dyno result to me. you can't guess at fly wheel horsepower with these cars, they probably only have about 10% drivetrain loss. There is very little drivetrain loss compared to older cars, or even the 05-10 mustangs. electric fuel pumps and steering. that's why they don't make Under-drive pulleys for these cars.
here is one with a tune and cat-back, 403whp:
http://www.youtube.com/watch?v=TwHos830Y_Y
ive seen 395-400whp tune only. so he may have picked up 5-10 with the kooks cat-back system. kooks does make good exhaust. I've seen a lot of people with just a cai+tune put down 405whp too though.
okay so for a full cat-back system you might gain 5-10whp, from a good system. most people doing an off-road mid-pipe see a 15whp gain, and doing axle-backs see no gain. maybe the engine will put out an extra few hp, but it isn't anything you can measure at a dragstrip. if it doesn't drop a tenth off your 1/4 ET, the mod isn't a performance mod. I've never heard of someone dropping .1 from a cat-back system (requires 10whp to drop a tenth on average) but maybe it's possible.
you can see truckguy's post here:
http://www.svtperformance.com/forums...k-times-4.html
he has a cat-back system, bunch of suspension, MT drag radials, runs 12.0@113. That is close to what most people run with tune+drag radials only, with that trap he is running about as good as it gets. that is what many tune-only traps see. and that is a good way to measure overall power output of a vehicle, about the same as a tune only car.
here you can see steeda ran 11.9@115 cai+tune only.
http://www.youtube.com/watch?v=xFf2EWQ3wTE
this guy ran 12.2@112mph tune-only
http://www.modularfords.com/f259/bbr...hs-off-169510/
it's hard to find many cat-back+tune only times but it looks like from my research the cai+tune is better, and most people only gain about 10-15whp out of the cai. leaving me to believe the cat-back does next to nothing for power.
here is one with a tune and cat-back, 403whp:
http://www.youtube.com/watch?v=TwHos830Y_Y
ive seen 395-400whp tune only. so he may have picked up 5-10 with the kooks cat-back system. kooks does make good exhaust. I've seen a lot of people with just a cai+tune put down 405whp too though.
okay so for a full cat-back system you might gain 5-10whp, from a good system. most people doing an off-road mid-pipe see a 15whp gain, and doing axle-backs see no gain. maybe the engine will put out an extra few hp, but it isn't anything you can measure at a dragstrip. if it doesn't drop a tenth off your 1/4 ET, the mod isn't a performance mod. I've never heard of someone dropping .1 from a cat-back system (requires 10whp to drop a tenth on average) but maybe it's possible.
you can see truckguy's post here:
http://www.svtperformance.com/forums...k-times-4.html
he has a cat-back system, bunch of suspension, MT drag radials, runs 12.0@113. That is close to what most people run with tune+drag radials only, with that trap he is running about as good as it gets. that is what many tune-only traps see. and that is a good way to measure overall power output of a vehicle, about the same as a tune only car.
here you can see steeda ran 11.9@115 cai+tune only.
http://www.youtube.com/watch?v=xFf2EWQ3wTE
this guy ran 12.2@112mph tune-only
http://www.modularfords.com/f259/bbr...hs-off-169510/
it's hard to find many cat-back+tune only times but it looks like from my research the cai+tune is better, and most people only gain about 10-15whp out of the cai. leaving me to believe the cat-back does next to nothing for power.
04-08-2012, 07:44 PM
#12
Mish-ogynist
Join Date: Nov 2007
Location: Helena, MT
Posts: 3,780
that doesn't even make sense. I don't believe the heartthrob video, sounds like BS, i've never heard anyone report anything like that about an X pipe over an H pipe and I don't see any dragstrip video to back up his claims. dynos can read whatever you want them to read. If heartthrob was a well known and reputable supplier I wouldn't immediately dismiss it like this, but his numbers aren't anywhere near any other hp figures i've seen anywhere and it just doesn't add up to what other people are reporting for an x vs h pipe in these cars. which is no difference in power, just a difference in sound, h-pipe tends to sound raspier. If i saw several other claims like heartthrobs i'd have to see how that was even possible. x pipes generally flow a bit better than Hs.
you can also take it from a major exhaust manufacturer
http://www.flowmastermufflers.com/index.php?page=56
likely if an x pipe did produce less power it's because they screwed up the design causing turbulence where it merges. and based on how narrow that X was on their pipe maybe thats possible, look at the angle of the exhaust that they made, much narrower than other X pipes i've seen. but again, there is no way he got 21hp out of a cat-back system. that is closer to full LT header, high-flowcat exhaust numbers.
http://www.youtube.com/watch?v=Kprbn1NrmoA
this was written by a moderator here:
http://www.examiner.com/autos-in-det...-xtreme-system
they saw a 6whp and 3wtq gain from changing mufflers.... except that I've seen that much difference between dyno runs w/o doing anything to the car so i again, feel there is no change in power from axle back. which is why most people might post a 5-10whp gain over stock using a cat back system. the track numbers dont show any change in power, no higher traps, no lower ETs from any runs i've seen.
I'm just in here showing you more sources so you don't throw your money into a mod that you think will give you more power but wont. If you think the exhaust sounds good and its worth the cost for it to you then go for it. But I don't believe those power increases, and I don't think you'll see any so I don't want you to feel you got cheated or that certain exhaust mods wont give you power.
If you want to get it and do your own testing that would be awesome, I would love to see your results. If heartthrob was claiming the same hp numbers as the major manufacturers I'd say cool go for it, they are cheap and same #s, but since he is claiming as much as most full LT header exhaust systems from big companies with a lot of R&D I have to say BS.
you can also take it from a major exhaust manufacturer
http://www.flowmastermufflers.com/index.php?page=56
likely if an x pipe did produce less power it's because they screwed up the design causing turbulence where it merges. and based on how narrow that X was on their pipe maybe thats possible, look at the angle of the exhaust that they made, much narrower than other X pipes i've seen. but again, there is no way he got 21hp out of a cat-back system. that is closer to full LT header, high-flowcat exhaust numbers.
http://www.youtube.com/watch?v=Kprbn1NrmoA
this was written by a moderator here:
http://www.examiner.com/autos-in-det...-xtreme-system
they saw a 6whp and 3wtq gain from changing mufflers.... except that I've seen that much difference between dyno runs w/o doing anything to the car so i again, feel there is no change in power from axle back. which is why most people might post a 5-10whp gain over stock using a cat back system. the track numbers dont show any change in power, no higher traps, no lower ETs from any runs i've seen.
I'm just in here showing you more sources so you don't throw your money into a mod that you think will give you more power but wont. If you think the exhaust sounds good and its worth the cost for it to you then go for it. But I don't believe those power increases, and I don't think you'll see any so I don't want you to feel you got cheated or that certain exhaust mods wont give you power.
If you want to get it and do your own testing that would be awesome, I would love to see your results. If heartthrob was claiming the same hp numbers as the major manufacturers I'd say cool go for it, they are cheap and same #s, but since he is claiming as much as most full LT header exhaust systems from big companies with a lot of R&D I have to say BS.
Last edited by Mishri; 04-08-2012 at 08:15 PM.
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